<!DOCTYPE HTML>
<canvas width="100" height="100" id="c"></canvas>
<script>
window.onload = function () {
    var ctx = document.getElementById('c').getContext('2d');

    ctx.beginPath();
    ctx.moveTo(0, 0);
    ctx.lineTo(0, 100);
    ctx.lineTo(100, 100);

    ctx.fillStyle = '#f00';
    ctx.strokeStyle = '#00f';

    ctx.fillRect(30, 10, 10, 10);
    ctx.strokeRect(60, 10, 10, 10);
    ctx.clearRect(25, 15, 50, 10);
    ctx.drawImage(document.getElementById('c'), 0, 0);
    if (ctx.putImageData) ctx.putImageData(ctx.getImageData(0, 0, 10, 10), 0, 0);

    ctx.lineTo(100, 0);
    ctx.fillStyle = '#0f0';
    ctx.fill();
}
</script>
